Use of feeding rate and re-pairing of precopulatory Gmmarus pulex to assess toxicity of gamma-hexachlorocyclohexane (lindane)

Feeding rate and re-pairing of physically pre-disrupted precopulatory Gammarus pulex were applied as response criteria to assess toxicity of Gamma-hexachlorocyclohexane (lindane). Animals were exposed to either high [0.5 – 2.0 mg 1−1] concentrations for 2 – 20 min or low [0.5 – 5.0 μg 1−1] concentrations for 48 h at 15° C. Feeding rate was significantly reduced during 48 h exposure to 5.0 μg 1−1 lindane (6% of the 48 h LC50) although precopulation was essentially unaffected. The majority of pre-disrupted couples re-paired after the feeding period, and no significant disruptive effect on non-disrupted pairs exposed to low concentrations occurred. Feeding rate was also significantly reduced during the first 24 h post brief-exposure [2 – 20 min] to lindane at 2.0 mg 1−1 and at 1.0 mg 1−1 for 20 min. Re-pairing was affected by treatments combining higher concentrations and longer exposures. The median survival time of briefly exposed animals varied with concentration and exposure period.